Control knob with variable core depth

ABSTRACT

A control knob design that is usable on the shaft of an adjustable control device for a variety of design applications. In order to standardize knob designs so as to reduce large inventory problems, the knob is supplied with a spring retention clip that cooperates with the hub of the knob that is formed with a series of descending steps such that the clip member may seat on any one of the steps and create a variable core depth for accommodating different shaft lengths of the control devices.

United States Patent [191 Keeling, Jr.

[ CONTROL KNOB WITH VARIABLE CORE DEPTH [75] Inventor: Kermit B. Keeling, Jr., Louisville,

[73] Assignee: General Electric Company,

Louisville, Ky.

[22] Filed: Sept. 29, 1972 [2]] Appl. No.: 293,554

52 us. (:1 74/553, 287/53 H 51 Int. Cl G05g 1/12 [58] Field of Search 74/553; 287/53 H, 53 R [56] References Cited UNITED STATES PATENTS 1,911,916 5/1933 Menamin 287/53 H FOREIGN PATENTS OR APPLICATIONS 1,058,312 2/1967 Great Britain 287/53 H Apr. 23, 1974 Primary Examiner-Benjamin W. Wyche Assistant ExaminerF. D. Shoemaker Attorney, Agent, or Firm-Richard L. Kaslin; Francis H. Boos, Jr.

[ 7] ABSTRACT A control knob design that is usable on the shaft of an adjustable control device for a variety of design applications. ln order to standardize knob designs so as to reduce large inventory problems, the knob is supplied with a spring retention clip that cooperates with the hub of theknob that is formed with a series of descending steps such that the clip member may seat on any one of the steps and create a variable core depth for accommodating different shaft lengths of the control devices.

8 Claims, 3 Drawing Figures 1 CONTROL KNOB WITH VARIABLE CORE DEPTH BACKGROUND OF THE INVENTION Appliance manufacturers that make appliances that use rotary control devices such as multiple position electrical switches and thermostats require a rotary control knob for each device. Particular reference is made here to manufacturers of ranges, automatic wash- One example in the prior art of a control knob with an adjustable connection so that it may accommodate many different control devices that have different orientations of the flat side of the D-shaped shaft of the devices is the patent of George R. Sherman US. Pat. No. 3,543,605, which is assigned to the General Electric Company, the assignee of the present invention. This patent discloses a knob design where it is possible to alter the angular relationship between the control knob and the mounting shaft of the control device by use of a generally flat clip member confined between a pair of a large choice of opposing slots in the bore of the hub of the knob to establish a D-shaped bore for receiving the mating shaft.

The principle object of the present invention is to provide a control knob with a variable core depth for accommodating different lengths of mounting shafts.

A further object of the present invention is to provide a rotary control knob with'a novel retention clip for use in the bore of the knob for engaging the shaft whereby the shim may be adjusted in its position to alter the depth of the bore.

A further object of the present invention is to provide a rotary control knob. of the class described with a hub having a series of spiral steps, any one of which will accommodate the retention shim at various positions so as to create different depths of the bore of the knob.

SUMMARY OF THE INVENTION The present invention, in-accordance with one form thereof, relates to a rotary control knob with a front handle portion and a rear hub portion where the hub has a bore which may extend into the handle portion. The wall of the hub is formed with a series of declining steps and there is an adjustable retention clip of spring material for securing the control knob to the shaft. This clip has an intermediate shank portion with a shaft stop at one end and a head portion at the other end which is adapted to Seat on one of the steps of the hub thereby providing a variable depth of the bore for accommodating mounting shafts of different lengths.

BRIEF DESCRIPTION OF THE DRAWINGS My invention will be betterunderstood from the following description taken in conjunction with the accompanying drawings and its scope will be pointed out in the appended claims.

FIG. 1 is an exploded view showing a rotary control knob of the present invention with the retention clip separated therefrom, as well as the nature of the cylindrical hub of the knob and the series of spiral descending steps formed in the wall of the-hub for accommodating the shim at various levels in order to vary the depth of the bore of the handle for accommodating the mounting shaft of a control device.

FIG. 2 is a cross-sectional elevational view showing the control knob of FIG. I mounted on the shaft of a control device such as a multiple position selector switch where the length of the shaft is of medium length.

FIG. 3 is a cross-sectional elevational view similar to that of FIG. 2 where the rotary control knob of the present invention is shown mounted on a longer shaft, where the position of the retention shim has been shifted to its lowest position in order to shift the position of the shaft stop of the shim to accommodate a longer mounting shaft.

DESCRIPTION OF THE PREFERRED EMBODIMENT or dial 14 formed therewith as well as a hollow cylindri-- calhub 16 on the rear of the handle portion. This invention is centeredaround the method of connecting the hub 16 of the knob 10 with a supporting shaft 18 of a control device 20 as is seen in FIG. 2. The exact design or appearance of the front handle portion 12 and dial 14 of the knob is not critical to the practice of the present invention.

The hub 16 is provided with a cylindrical bore 24 that has a non-circular cross-section by virtue of a flat side 26 for accommodating a mating shaft 18 of a rotary control device 20. This bore 24 not only extends through the hub 16 but it also extends deep into the handle portion 12 as is clear from FIG. 2. The cylindrical bore 24 transforms the hub 16 into a hollow member with a cylindrical wall 28. This wall is formed with a spiral series of descending steps such as steps 29, 30, 31 and 32.

A shaft retention clip or shim 35 is furnished for insertion into the bore 24 of the knob. This retention shim is formed of spring steel and it has a shank portion 37 with a shart stop 39 at one end and a head portion 41 at the opposite end. The shaft stop is arranged at a transverse angle from the shank portion37 so that the tip of the shaft 18 will engage the stop 39 and the knob will be in its final resting place.

The head portion'4l oithe retention shim 35 is also formed at a transverse angle to the shank 37 but in a direction opposite to the shaft stop 39 so that the head portion can seat on one of the steps 29, 30, 31 or 32. It is well to attach the retention shim 35 so that it does not slip from the knob when the knob is separated from the shaft 18. For this reason the head 41 is provided with a locking flange or down-turned tab 43 which is adapted to pinch the cylindrical wall 28 of the hub with a forced fit as is clear from FIGS. 2 and 3. The control device 20 would be mounted on a control panel (not shown) and usually there is a crystal or front panel 47 mounted in front of the control device. This panel is provided with an oversized opening 49 for accommodating the hub 16 of the control knob 10 as well as the shaft 18 which telescopes into the knob. Notice in comparing FIGS. 2 and 3 that while the shaft 18 of FIG. 2 is longer than the shaft 18 of FIG. 3 the relative position of the control knob with respect to the crystal 4'! is the same. This of course is due to the cooperation between the retention shim 35 and the spiral steps 29 32 of the hub of the control knob as was explained above. I Modifications of this invention will occur to those skilled in this art. Therefore, it is to be understood that this invention is not limited to the particular embodiments disclosed but that it is intended to cover all modifications and their equivalents which are within the true spirit and scope of this invention as claimed.

. What is claimed as new and desired to be secured by Letters Patent of the United States is:

l. A control knob for connection with a mounting shaft of an adjustable device which may be manipulated by rotation of said knob, the knob having a handle portion and a cylindrical hub with a cylindrical bore extending through the hub and into the handle portion, the bore forming with the hub a cylindricalwall, and a series of spiral descending steps formed on the top edge of the cylindrical wall, and a clip member having a shank portion, a head portion, and a foot portion, the head portion being adapted to seat on one of the said steps, the shank portion extending into the cylindrical bore and adapted to exert a holding pressure against a mounting shaft on which the knob is to be carried, the said foot portion being adapted to engage the end of the mounting shaft and serve as a stop means to limit the amount of movement of the knob onto the shaft.

2.- A control knob as recited in claim 1 wherein the head portion of the said clip member has. a locking flange that is adapted to grip the cylindrical wall and retain the clip member in place.

,3. A control knob having a handle with a hollow cylindrical hub arranged to receive an operating shaft of an associated control device which is to be adjusted'by rotation of said knob, the hollow hub having a noncircular cylindrical bore which extends into the handle, the hub having a cylindrical wall with a spiral series of steps, and a metal shim having a head at one end, a shaft stop at the opposite end, and an intermediate shank portion, the head of the shim being seated on one of the spiral steps with the shank portion extending into the bore, the said shaft stop serving as a limit means to control the position of the knob on the shaft, the shank portion serving to apply pressure against the shaft for knob retention, and means to attach the shim to the knob against accidental displacement.

'4. A control knob as recited in claim 3 wherein the means for attaching the shim to the knob is a downturned outer edge of the head of the shim which serves to pinch the cylindrical wall with a forced fit.

5. An adjustable retention clip of resilient material for securing a control knob to the end of a shaft, said clip comprising an elongated shank portion of longitudinally bowed configuration with a transverse head portion at one end and an oppositely turned transverse shaft stop portion at the opposite end, the said transverse head portion having a transverse inwardly-turned tab at its end which cooperates with the shank portion and is adapted to grip a wall portion of the knob therebetween so as to be able to fasten the retention clip to a control knob.

6. A rotary control knob for connection with the end of a shaft of an adjustable control device which may be manipulated by rotation of said knob, the knob having a front handle portion and a rear hub portion, the hub portion having a D-shaped bore which also extends into the handle portion, the wall of the hub being formed with a series of descending steps, and an adjustable retention clip of spring material for securing the control knob to the said shaft, said clip having an elongated shank portion with a transverse head portion at one end and an oppositely turned transverse shaft stop portion at the opposite end, the said head portion being adapted to seat upon any one of the said steps on the wall of the hub so as to provide a control knob with a variable core depth.

7. A rotary control knob as recited in claim 6 wherein the head portion of the retention clip is formed with means for attaching the clip to the wall of the hub.

8. A rotary control knob as recited in claim 6 wherein the head portion of the retention clip is formed with a gripping tab that has a forced fit against the exterior of the wall of the hub. 

1. A control knob for connection with a mounting shaft of an adjustable device which may be manipulated by rotation of said knob, the knob having a handle portion and a cylindrical hub with a cylindrical bore extending through the hub and into the handle portion, the bore forming with the hub a cylindrical wall, and a series of spiral descending steps formed on the top edge of the cylindrical wall, and a clip member having a shank portion, a head portion, and a foot portion, the head portion being adapted to seat on one of the said steps, the shank portion extending into the cylindrical bore and adapted to exert a holding pressure against a mounting shaft on which the knob is to be carried, the said foot portion being adapted to engage the end of the mounting shaft and serve as a stop means to limit the amount of movement of the knob onto the shaft.
 2. A control knob as recited in claim 1 wherein the head portion of the said clip member has a locking flange that is adapted to grip the cylindrical wall and retain the clip member in place.
 3. A control knob having a handle with a hollow cylindrical hub arranged to receive an operating shaft of an associated control device which is to be adjusted by rotation of said knob, the hollow hub having a non-circular cylindrical bore which extends into the handle, the hub having a cylindrical wall with a spiral series of steps, and a metal shim having a head at one end, a shaft stop at the opposite end, and an intermediate shank portion, the head of the shim being seated on one of the spiral steps with the shank portion extending into the bore, the said shaft stop serving as a limit means to control the position of the knob on the shaft, the shank portion serving to apply pressure against the shaft for knob retention, and means to attach the shim to the knob against accidental displacement.
 4. A control knob as recited in claim 3 wherein the means for attaching the shim to the knob is a downturned outer edge of the head of the shim which serves to pinch the cylindrical wall with a forced fit.
 5. An adjustable retention clip of resilient material for securing a control knob to the end of a shaft, said clip comprising an elongated shank portion of longitudinally bowed configuration with a transverse head portion at one end and an oppositely turned transverse shaft stop portion at the opposite end, the said transverse head portion having a transverse inwardly-turned tab at its end which cooperates with the shank portion and is adapted to grip a wall portion of the knob therebetween so as to be able to fasten the retention clip to a control knob.
 6. A rotary control knob for connection with the end of a shaft of an adjustable control device which may be manipulated by rotation of said knob, the knob having a front handle portion and a rear hub portion, the hub portion having a D-shaped bore which also extends into the handle portion, the wall of the hub being formed with a series of descending steps, and an adjustable retention clip of spring material for securing the control knob to the said shaft, said clip having an elongated shank portion with a transverse head portion at one end and an oppositely turned transverse shaft stop portion at the opposite end, the said head portion being adapted to seat upon any one of the said steps on the wall of the hub so as to provide a control knob with a variable core depth.
 7. A rotary control knob as recited in claim 6 wherein the head portion of the retention clip is formed with means for attaching the clip to the wall of the hub.
 8. A rotary control knob as recited in claim 6 wherein the head portion of the retention clip is formed with a gripping tab that has a forced fit against the exterior of the wall of the hub. 